Two-storey extensions for semi-detached houses in West Ealing
Adding a two-storey extension for a semi-detached house in West Ealing gives you two new rooms stacked on one footprint. Here's how we'd approach it, what it typically costs and the rules that apply in England.
What we'd confirm first for a project in West Ealing.
- Postcode districts
- W7 and W13
- County / area
- Greater London, England
- Price region
- London
- Guide price
- £67,000–£90,500 (£2,400–£3,240 per m²)
- Approval route
- Depends on position: a two-storey rear extension may be permitted development (3 m deep, 7 m from the rear boundary); a two-storey side extension needs planning permission.
- Nearest towns
- Ealing (0.6 miles), Ealing Common (1.3 miles), Greenford (1.7 miles)
- First visit
- Free, no obligation
About a two-storey extension for a semi-detached house
This service suits you if you own a semi-detached house and want to add bedrooms and living space without moving. On a semi, the main questions are which side to build on and how to treat the attached neighbour. You get a survey, design options, the approvals your nation needs and the build, carried out by vetted teams working under S&K.
Around West Ealing we also work in Ealing, Ealing Common and Greenford, and across the rest of Greater London. Postcode districts in and near West Ealing: W7 and W13.
What it costs in West Ealing
Guide prices for two-storey extensions for semi-detached houses in London are around £2,400–£3,240 per m² of new floor space, including VAT. For a typical project with a 4 m × 3.5 m footprint on two floors (28 m² of new floor space), that's roughly £67,000–£90,500. Professional fees for drawings and the structural engineer are listed separately on our prices page.
| Spec | Per m² | A 4 m × 3.5 m footprint on two floors (28 m² of new floor space) |
|---|---|---|
| Essential | £2,210–£2,980 per m² | £62,000–£83,500 |
| Standard | £2,400–£3,240 per m² | £67,000–£90,500 |
| Premium | £2,880–£3,890 per m² | £80,500–£109,000 |
Planning and building regulations in West Ealing
In England, a two-storey rear extension on a semi can be permitted development if it goes no more than 3 m beyond the original rear wall and stays 7 m from the rear boundary, with matching materials and roof pitch. A two-storey side or wraparound extension always needs planning permission, costing £548 (or £575 for applications made from 8 December 2026). Protected areas such as conservation areas exclude two-storey rear permitted development.
Approval in England: Householder planning application: £548 (or £575 for applications made from 8 December 2026). Lawful development certificate: £274 (about £288 for applications from 8 December 2026). Councils should decide householder applications within 8 weeks of validation.
Building regulations: Building regulations approval (full plans recommended) from the council or a registered building control approver, with a completion certificate at the end.
Design points for West Ealing homes
Keeping the pair balanced
Semis are designed as matching pairs, and a side extension changes that balance. Setting the side extension back from the front wall and keeping its ridge lower helps the pair still read as a pair, which councils' design guides commonly ask for.
The attached neighbour's light
A two-storey rear extension next to the party wall can take light from the neighbour's rear windows. Councils often use a 45-degree test, so the first floor may need to be shorter than the ground floor or set in from the shared boundary.
How we'd run your project
Visit and first ideas
One of our team visits your house in West Ealing, checks the walls, roof and drains, and sketches out options with you.
Drawings and permission
Our designers produce plans and elevations, then we take care of planning or permitted development checks with the council covering West Ealing.
Technical design
We prepare the building regulations drawings, structural calculations and specification so the build price can be fixed.
Build and sign-off
Vetted teams working under S&K build the extension, and we arrange the building control completion certificate at the end.
Questions about two-storey extensions for semi-detached houses in West Ealing
Do I need planning permission for a two-storey extension for a semi-detached house in West Ealing?
West Ealing is in England, so England planning rules apply. Depends on position: a two-storey rear extension may be permitted development (3 m deep, 7 m from the rear boundary); a two-storey side extension needs planning permission. If in doubt, a lawful development certificate or a planning application gives you certainty before you build.
Who handles building regulations for a project in West Ealing?
We handle it as part of the project. What's needed in England: building regulations approval (full plans recommended) from the council or a registered building control approver, with a completion certificate at the end. We prepare the drawings and the engineer's calculations, book the inspections and pass you the completion paperwork at the end.
How long does a two-storey extension for a semi-detached house take?
Allow 4 to 8 weeks for survey and design, then the approval period (councils should decide householder applications within 8 weeks of validation), then 4 to 8 weeks of technical design, which can overlap. The build itself usually takes 14 to 20 weeks, longer for large or complex designs.
Should I extend my semi to the side or the rear?
It depends on your plot and what you need. A rear extension keeps the side drive and can sometimes be permitted development, but it affects the attached neighbour. A side extension keeps the rear garden but always needs planning permission in England. We compare both at the free site visit.
Does a two-storey extension add value to a semi-detached house?
It usually adds value, but the gain is never certain. Nationwide's 2025 research found that 10% more floor area was linked to about 5% higher value, and that adding a double bedroom and bathroom to a three-bed, one-bathroom house could add up to 24%. Every street has a ceiling price, so check local sales first.
Nearby
Other towns near West Ealing:
Other extensions in West Ealing
- Rear
- Side
- Wraparound
- Part two-storey
- Over a garage
- First floor
- Detached
- Kitchen and bedrooms
- Bedroom and en-suite
All two-storey extension services in West Ealing · Two-storey extensions for semi-detached houses across Greater London
Ready to talk it through? Call us or send the form and we'll arrange a visit to your home in West Ealing.